Bio Section 11-12 Flashcards
What are the two subdivisions of the nervous system?
Central and Peripheral
What are the components of the CNS?
Brain and spinal cord
What are the components of the PNS?
Everything but the Brain and spinal cord
What are nerves?
A bundle of nerve fibers (axons) wrapped in fibrous connective tissue
Ganglion?
A knot-like swelling in a nerve where neuron cell bodies are concentrated.
Does the PNS contain sensory and motor divisions?
Yes and the divisions each have somatic and visceral subdivisions
What does the Sensory division do?
Carries singles from receptors to the CNS
What does the Somatic sensory division do?
Carries singles from receptors in the skin. muscles. bones, and joints to the CNS
What does the Visceral sensory division do?
Carries singles from the viscera (heart, lungs, stomach, and urinary bladder) to the CNS
What does the motor (effernt) division do?
Carries signals from the CNS to effectors ( glands and muscles that carry out the body response.
What does the Somatic motor division do?
Carries signals to the skeletal muscles
What does the Visceral motor division do?
Carries signals to the glands, cardiac and smooth muscle.
The visceral motor division is further divided into two more categories called?
Sympathetic and Parasympathetic division.
What is the function of the sympathetic division?
It tends to arouse body actions.
Accelerating heartbeat and respiration, while inhibiting digestive and urinary systems
What is the function of the Parasympathetic division?
Has a calming effect
Slows heart rate and breathing
Stimulates digestive and urinary systems
What are the three universal properties of neurons?
Excitability
Conductivity
Secretion
What is excitability?
It is the response to environmental changes called stimuli
What is Conductivity?
Response to stimuli by producing electrical signals that are quickly conducted to other cells at distant locations.
What is Secretion?
When an electrical signal reaches the end of a nerve fiber, the cell secrets a chemical neurotransmitter that influences the next cell.
What are the three functional classes of neurons?
Sensory (afferent)
Interneurons
Motor (efferent)
What is the function of the Sensory neurons?
TO detect stimuli and transmit information about them toward the CNS
Where are the Interneurons located?
Entirely within the CNS connecting motor and sensory pathways (about 90% of all neurons)
What is the function of the interneurons?
They receive signals from many neurons and carry out integrative functions.
What is the function of a motor (efferent) neuron?
They send signals out to muscles and gland cells ( the effectors)
What is the control center of neurons?
Neurosoma (cell body)
What is a characteristic of Neurosoma?
It has a single centrally located nucleus with a large nucleolus.
What does the cytoplasm contain?
Mitochondria
Lysosomes
Golgi complex
Inclusions
Extensive rough ER
Cytoskeleton
What are dentrites?
They are branches that come off the neirosoma
What is the function of dendrites?
The receive signals from other neurons
What does it mean if I say Multipolar neuron?
It has one axon and multiple dendrites
Most commonly found in the CNS
What does it mean if I say Bipolar neuron?
It was one axon and one dendrite
Olfactory cells, retina, inner ear.
What does Unipolar neuron mean?
The single process leading away from the neuron soma
Sensory cells from the skin and organs to spinal cord
What does Anaxonic neuron mean?
Many dendrites but no axon
Retina, brain, adrenal gland
What are the four types of glia that occur in the CNS?
Oligodendrocytes
Ependymal cells
Microglia
Astrocytes
What is the function of the Oligodendrocytes?
To form myelin sheaths in the CNS that speed signal conduction.
What is the function of the Ependymal cells?
They line the internal cavities of the brain; secrete and circulate cerebrospinal fluid CSF
What is the function of the Microglia?
They wander through the CNS looking for debris and damage to be fixed.
What is the most abundant glial cell in the CNS?
Astrocytes
Is it true that Astrocytes can only perform one function?
That is false. They have a diverse abilities for functions.
What are the two types of cells that occur in the PNS?
Schwann
Satellite
What are the functions of the Schwann Cells?
They wind repeatedly around a a nerve fiber
Assist in regeneration of damages fibers
Produce myelin sheath similar to the ones in the CNS
What is a Myelin sheath?
It is insulation around nerve fiber.
What is Myelination?
It is the production of the myelin sheath.
When does Myelination begin?
At 14 weeks of fetal development and is completed in late adolescence
What is a tumor?
It is a mass of rapidly dividing cells.
What do brain tumors arise from?
Meninges
Metastasis from nonneuronal tumors in other organs
What decreases the effectiveness of chemotherapy?
Blood-brain barriers
What are two diseases caused by the myelin sheath
Multiple sclerosis
Tay-Sachs
What is Tay-Sachs disease?
It is a hereditary disorder of infants of Eastern European Jewish ancestry.
Small unmyelinated fiber conduct speed at?
0.5 to 2.0 m/s
Small myelinated fibers conduct speed at?
3 to 15.0 m/s
Large myelinated fibers conduct speed at?
up to 120m/s
Where are the slow signals sent?
The gastrointestinal track.
Where are fast signals sent?
Skeletal muscles
